feat(measurexlite): Trace now implements MeasuringNetwork (ooni#1262)

This diff is still yak shaving for
ooni/probe#2531 but produces some nice side
effects. Now, we can either use netxlite.Netx or measurexlite.Trace as a
dependency for measuring code.

The cost of this change is (1) switching some functions to use a
`model.DebugLogger`, which is not an issue, and (2) adding some optional
wrappers to other functions. I made these functions to ignore the
wrappers and documented this limitation, because measurexlite code does
not need this functionality. It is a bit debateable whether this is the
best way to implement this change, but I am doing this because I would
like to see these wrappers gone when we stop using legacy/netx in the
codebase, so I think it's fine to ignore them, to better signal they're
deprecated stuff.

This change is absolutely in line with the original spirit of
measurexlite because it's now much simpler to write code for netxlite
and then upgrade to measurexlite.

I noticed this possibility yesterday while working on a much larger
diff, and now I am committing this smaller diff to start the working
day.

internal/measurexlite/dialer.go

@@ -18,7 +18,10 @@ import (
 
 // NewDialerWithoutResolver is equivalent to netxlite.NewDialerWithoutResolver
 // except that it returns a model.Dialer that uses this trace.
-func (tx *Trace) NewDialerWithoutResolver(dl model.DebugLogger) model.Dialer {
+//
+// Caveat: the dialer wrappers are there to implement the [model.MeasuringNetwork]
+// interface, but they're not used by this function.
+func (tx *Trace) NewDialerWithoutResolver(dl model.DebugLogger, wrappers ...model.DialerWrapper) model.Dialer {
 	return &dialerTrace{
 		d:  tx.Netx.NewDialerWithoutResolver(dl),
 		tx: tx,

internal/measurexlite/dns.go

@@ -92,17 +92,17 @@ func (r *resolverTrace) LookupNS(ctx context.Context, domain string) ([]*net.NS,
 }
 
 // NewStdlibResolver returns a trace-ware system resolver
-func (tx *Trace) NewStdlibResolver(logger model.Logger) model.Resolver {
+func (tx *Trace) NewStdlibResolver(logger model.DebugLogger) model.Resolver {
 	return tx.wrapResolver(tx.Netx.NewStdlibResolver(logger))
 }
 
 // NewParallelUDPResolver returns a trace-ware parallel UDP resolver
-func (tx *Trace) NewParallelUDPResolver(logger model.Logger, dialer model.Dialer, address string) model.Resolver {
+func (tx *Trace) NewParallelUDPResolver(logger model.DebugLogger, dialer model.Dialer, address string) model.Resolver {
 	return tx.wrapResolver(tx.Netx.NewParallelUDPResolver(logger, dialer, address))
 }
 
 // NewParallelDNSOverHTTPSResolver returns a trace-aware parallel DoH resolver
-func (tx *Trace) NewParallelDNSOverHTTPSResolver(logger model.Logger, URL string) model.Resolver {
+func (tx *Trace) NewParallelDNSOverHTTPSResolver(logger model.DebugLogger, URL string) model.Resolver {
 	return tx.wrapResolver(tx.Netx.NewParallelDNSOverHTTPSResolver(logger, URL))
 }
 

internal/measurexlite/quic.go

@@ -16,7 +16,11 @@ import (
 
 // NewQUICDialerWithoutResolver is equivalent to netxlite.NewQUICDialerWithoutResolver
 // except that it returns a model.QUICDialer that uses this trace.
-func (tx *Trace) NewQUICDialerWithoutResolver(listener model.UDPListener, dl model.DebugLogger) model.QUICDialer {
+//
+// Caveat: the dialer wrappers are there to implement the [model.MeasuringNetwork]
+// interface, but they're not used by this function.
+func (tx *Trace) NewQUICDialerWithoutResolver(
+	listener model.UDPListener, dl model.DebugLogger, wrappers ...model.QUICDialerWrapper) model.QUICDialer {
 	return &quicDialerTrace{
 		qd: tx.Netx.NewQUICDialerWithoutResolver(listener, dl),
 		tx: tx,

internal/measurexlite/trace.go

@@ -75,6 +75,8 @@ type Trace struct {
 	ZeroTime time.Time
 }
 
+var _ model.MeasuringNetwork = &Trace{}
+
 // NetworkEventBufferSize is the [*Trace] buffer size for network I/O events.
 const NetworkEventBufferSize = 64
 

internal/measurexlite/udp.go

@@ -0,0 +1,7 @@
+package measurexlite
+
+import "github.com/ooni/probe-cli/v3/internal/model"
+
+func (tx *Trace) NewUDPListener() model.UDPListener {
+	return tx.Netx.NewUDPListener()
+}

internal/measurexlite/udp_test.go

@@ -0,0 +1,24 @@
+package measurexlite
+
+import (
+	"testing"
+	"time"
+
+	"github.com/ooni/probe-cli/v3/internal/mocks"
+	"github.com/ooni/probe-cli/v3/internal/model"
+)
+
+func TestNewUDPListener(t *testing.T) {
+	// Make sure that we're forwarding the call to the measuring network.
+	expectListener := &mocks.UDPListener{}
+	trace := NewTrace(0, time.Now())
+	trace.Netx = &mocks.MeasuringNetwork{
+		MockNewUDPListener: func() model.UDPListener {
+			return expectListener
+		},
+	}
+	listener := trace.NewUDPListener()
+	if listener != expectListener {
+		t.Fatal("unexpected listener")
+	}
+}